1. Field of the Invention
The present invention relates to a manufacturing method of a liquid discharge head and an orifice plate, including discharge ports which discharge liquid droplets, individual liquid chambers which communicate with these discharge ports, and a piezoelectric member which is disposed in a vibration plate constituting a part of the individual liquid chambers and which is given a displacement that changes with an elapse of time to discharge the liquid droplets. The liquid discharge head of the present invention is applicable to an ink jet recording device which prints information on paper, cloth, leather, non-woven cloth and OHP sheet, a patterning device which attaches a liquid to a solid such as a substrate or a plate material, and a coating device. The liquid discharge head will hereinafter be referred to as typically the “ink jet head”.
2. Description of the Related Art
Heretofore, an ink jet head is incorporated for a broad range of application in recording devices such as a printer and a facsimile machine for reasons such as low noise, low running cost, a reason that the device is easily miniaturized and a reason that color printing is easily performed. Especially, applications of an ink jet head using a piezoelectric member have been enlarged as a patterning device for manufacturing a device owing to a high degree of freedom in selection of a liquid to be discharged.
The ink jet head generally has a channel substrate including a liquid channel, individual liquid chambers disposed at a first surface of the channel substrate, through paths extending from the individual liquid chambers to a second surface of the channel substrate, and an orifice plate bonded to the second surface of the channel substrate and provided with discharge ports which communicate with the through paths. To discharge ink droplets, the individual liquid chambers need to be pressurized. Examples of means for generating a pressure in the individual liquid chambers include a bubble type which foams the liquid with heat generators installed in the individual liquid chambers to discharge liquid droplets and a piezo type which deforms a vibration plate forming a part of the individual liquid chambers with a piezoelectric element to form the liquid droplets. Furthermore, an electrostatic type is also known which deforms the vibration plate with an electrostatic force to discharge the liquid droplets.
In such an ink jet head, in recent years, with a request for high definition of a formed image, the individual liquid chambers of the channel substrate and pressure generation sources such as the piezoelectric element are highly densely arranged in large amounts to achieve high integration. To meet such requirements, a piezo type ink jet head is proposed. In the head, electrodes and the piezoelectric member are formed on the whole surface of the vibration plate by a film forming technology, and the electrodes for the individual liquid chambers and the piezoelectric member are processed using a photolithography technology. Since the film forming technology and the photolithography technology are used, a highly dense ink jet head is realized.
Moreover, Japanese Patent Application Laid-Open No. H11-227204 discusses a technology in which electrodes and a piezoelectric film are formed on an Si substrate, and Si is then processed by anisotropic etching to highly precisely form the individual liquid chambers. However, in such an ink jet head, depths of the individual liquid chambers depend on a thickness of the substrate. The depths of the individual liquid chambers cannot freely be set. When the ink jet head is prepared using a comparatively large substrate having a size of six or eight inches, the substrate having a certain degree of thickness needs to be used so as to be easily treated during manufacturing. Therefore, the individual liquid chambers deepen. Especially the highly dense ink jet head has a structure including thin partition walls which separate the individual liquid chambers from one another, and the deep individual liquid chambers. Therefore, there are problems that sufficient rigidity is not obtained, crosstalk is generated and a desired discharge performance is not obtained.
To solve such a problem, Japanese Patent Application Laid-Open No. 2001-205808 discusses a manufacturing method in which grooves forming pressure generation chambers are formed at a single-crystal Si layer of an SOI substrate. After forming a sacrifice layer on the grooves, the vibration plate is formed. Finally, the sacrifice layer is removed to form shallow pressure generation chambers.
Moreover, Japanese Patent Application Laid-Open No. H05-229128 discusses a technology in which Si is processed from one surface of an Si substrate by use of anisotropic etching. In consequence, the individual liquid chambers and the through paths are formed at the Si substrate.
However, the manufacturing method of Japanese Patent Application Laid-Open No. 2001-205808 includes a complicated step of filling the grooves with the sacrifice layer. Moreover, the sacrifice layer is removed via narrow channels. There is also a problem that the sacrifice layer cannot completely be removed from the pressure generation chambers.
Furthermore, in the technology of Japanese Patent Application Laid-Open No. H05-229128, the liquid channels are formed using the anisotropic etching of Si. Since the depths of the liquid channels depend on widths thereof, both of the width and the depth of the liquid channel cannot be set to desired dimensions. Furthermore, in the technology of the Japanese Patent Application Laid-Open No. H05-229128, dimensions of the liquid channels also depend on a thickness of an Si wafer, and discharge ports cannot be formed separately into free dimensions. In addition, to prepare the highly dense ink jet head, the liquid channels need to be further miniaturized with high precision, and a constitution and a manufacturing method to achieve such an ink jet head are demanded.